The shipbuilding industry has directed much effort toward ways of limiting escalating coating costs. Of special concern with respect to increasing coating costs are segregated seawater ballast tanks. The use of a calcite-type coating instead of a traditional organic-type maintenance coating represents a possible alternative approach for controlling corrosion in the segregated tanks with a substantial savings in cost. As a result, National Steel and Shipbuilding Company acting on behalf of the Maritime Administration under the National Shipbuilding Research Program authorized the Ocean City Research Corporation to undertake a laboratory study which continued previous investigations of the feasibility of applying calcite-type coatings to segregated ballast tanks. The testing was intended to demonstrate and quantify the long-term corrosion protection afforded by the calcite coatings. The laboratory tests demonstrated that well developed calcite films can reduce the corrosion rate of steel in a seawater ballast tank. Furthermore, calcite films can reduce the cathodic protection current demand required for corrosion control by a factor of five. However, the testing also showed that calcite films will deteriorate with time upon continued exposure to seawater. Thus, such films would have to be periodically reformed given the contemplated approach.


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    Title :

    Corrosion Protection by Calcite-Type Coatings


    Contributors:

    Publication date :

    1989


    Size :

    42 pages


    Type of media :

    Report


    Type of material :

    No indication


    Language :

    English